Aircraft control surfaces



3, 1949. w. A. E. MITCHELL 2,480,040

' AIRCRAFT CONTROL SURFACES Filed Dec. 6, 1943 5 Sheets-Sheet 1.

IN VEN TOR.

Aug. 23, 1949.- w. A. E. MITCHELL 2,480,040

AIRCRAFT CONTROL SURFACES Filed Dec. 6, 1943 3 Sheets-Sheet 2 Flg. 5

1 N VEN TOR.

Aug. 23, 1949.. w. A. E. MITCHELL AIRCRAFT CONTROL SURFACES Fild Dec. 6, 1943 3 Sheets-Sheet 3 mm ON IIIIHI INVENTOR.

I mm Q R m Patented Aug. 23, 1949 UNITED STATES PATENT OFFICE AIRCRAFT CONTROL SURFACES Wilbur A. E. Mitchell, Greeley, Colo. Application December 6, 1943, Serial No. 513,112

4 Claims.

This invention relates to improvements in fluid .or aircraft control surfaces; and more particularly to improvements in the controlling system for guiding aircraft, with reference to auxiliary control surfaces, to assist the usual control means, or, in the alternative, to be used in lieu of the usual control means.

In aircraft, rudders, elevators and ailerons are commonly used as guiding or controlling means. It occasionally happens that said usual control means become insufficient or inoperative, and disaster follows from inability to control the ship.

One of the principal objects of my invention, therefore, is to provide auxiliary control means which can be put into service at will, either to assist in controlling the craft, for sufficient to operate in lieu of either one or more of the usual rudder, elevator or aileron controlling means, in event any one, more or all of said usual controlling means becomes inoperative in flight without notice, for any reason.

It often happens that the usual landing flap, or airbrake means, preparatory to landing, is insufiicient to slow the craft for a safe landing, and also that the wheel brake means upon landing is insuflicient to stop the plane within the length of the runway, for some reason in either event. such as excess or sudden change of wind or direction, or excess weight of the craft. It is therefore another object of my invention to provide auxiliary control means for guiding the craft which can also be used at will as auxiliary means for braking the craft, either in the air or upon landing while running on the ground, by retarding its speed.

It occasionally occurs in certain types of aircraft designed and required to dive from an extreme altitude, such as in dive bombers and pursuit ships of a military class, that the air pressure upon the dive pull-out, on the usual elevator means for pulling the ship out of the dive, is so great that said elevator means are then insufficient or inoperative. It is, therefore, another object of my invention to provide auxiliary control means for controlling or guiding an aircraft, which will also constitute air-braking means, when desired, to retard the rate or speed of dive or fall of a bomber, pursuit ship or other craft, either by way of ass sting the usual flap air-braking means, or act in lieu thereof, in the event same becomes damaged or inoperative.

It is a matter of common knowledge that one of the problems of aeronautics is to be able to raise large and heavy craft off of the ground in the take-off. It occasionally occurs that such craft are so bulky and heavy, proportionate to the motor-pull, wind resistance, construction of the craft and elevator means normally heretofore used, that difiiculty, and sometimes disaster, results from inability to lift the craft off of the ground sufliciently before reaching the end of the runway upon the take off. It is, therefore, another object of my invention, in connection with my provision of auxiliary controlling or guiding means for aircraft, to so construct said auxiliary control means that same can be called into service at will to assist the usual elevator means raise the ship upon the take-off, or take the place thereof if the usual elevator means fails completely to operate.

Another object of my invention is to so construct aircraft with control surfaces to assist or take the place of the commonly used or usual rudder, elevator or aileron control surfaces, respectively, that the assisting surfaces can, if desired, be placed forwardly of the assisted surfaces or usual rudder, elevator and ailerons; I accomplish this by constructing each assisting surface with a cut-away portion, whereby in operation thereof the following usual control surface will continue to receive a quantity or blast of air against its surface upon operation of both assisting and usual surfaces, as a result of the said cut-away portion of the assisting surfaces permitting a blast of air to pass through the assisting surface upon use, and thereby not preventing normal successful operation of the usual surfaces at the same time.

More particularly, it is the object of my invention to provide auxiliary control means in cooperation with usual control means, whereby each auxiliary control means is operable independently and separate from each other and from the usual control means, without interfering with the wind pressure normally against the usual means for successful operation thereof, whereby one can operate in conjunction with another for greater maneuverability of the craft or against that other for assisting in air-braking the speed of the craft.

Another object of my invention is to provide a control surface for guiding an airplane which permits a portion of the wind pressure built up in front of it, upon operation, to pass through it, without interfering with the successful operation thereof and as well without interfering with the successful operation of any part of the plane following in said line of wind pressure.

Another object of my invention is to provide auxiliary rudder and elevator control means for airplane; it is to be noted, however, that my said;

elevator controls could also be adapted with relation to the front wing of a plane as well as to the tail stabilizer portion, in eventmf, alone wing plane without a separate stabilizer as now used.

Several forms which the present invention may assume are shown for illustrative purposes in, the accompanying drawings, in which:

Figure 1 is a partiabperspective view, looking downwardly-upon thertail ofa transport airplane, on theground, having my auxiliary control means in association with the dorsal fin, stabilizer and 'fron 'win s.

'Eigure 2-isa partial perspective view; looking upwardly at the tail of a transport plane in flight,

haying-my stabilizer control means in association with the dorsal finv and stabilizer.

FiglllBBiS an enlargedpartial perspectiveiview .of;.one side of the stabilizer, asindicated by the lines 33 of Figure .1'.

Eigure 4' is. an enlarged, cross-sectional View, taken upon the line 4'--4.,of,Figure 3,,0fa sample construction of one of my auxiliarycontrol flaps,

said View illustrating them in association with, the

stabilizer. Thisis togbetaken as'illustr ative, also, ,ofihe construction ofmy said flaps shown in associatipnwith the dorsal fin and the front wings, as separate illustration thereof, WOll1d beduplicat ons.

Figure 5 is an elevat naln rspective view i1- us rative ive mber or, p rsuit shin, ina ne e div wherein, my auxiliary contr l means 2. nd. 2a, 21. and illhand 'maand. 11 nt e unner. desv i e stab lizers, and the, dorsal and. in. h ront. wines, sp ctively. are. in oo ra ivenos tion forassisfing,inair-brakin the es ent Qftlie raft, inlco perationwith the usual landing, flaps. nd, usual eleva ors, l5, and, in leyellingthe, craft on of he. dive...

.Eigure 6,. is a rear. .elevationall. vieWlof, the plane shown in Figure 5, after, ithas landed, showing my: xi ar rudder, oontrols Ill-and 12:1 .in airbraking, position, as an, example, in. cooperation with elevators l 5. landing .flaps, 8, and, the usual wheel brakes, .for, braking the speedbf the plane atter t-has landed andispoastiri .on therunway.

Eieure F7. is .a diagrammatic, representation of the r lativ operationslqf my, tendifierentauxiliary, controlfians on means, of the .pl-aneoffl eur 6, lo qki.n rearwardly, rom. he back,,as will be xplained.

.Ei ure is: a, diagram of one f, my, electrical circuits, forming the basis for others, used for onerat i er ain. of my uxiliary control surfaces o. and.

Eienre. 9., is. a. diaerammatical ill stration of, a uortion oi e steer ng, m chanism .of an aer plane, with cer tain switches associated therewith forcontrolline the eration of my. auxiliaryv flap suria es.

Referring now, more particularly to ,the drawings, the present invention comprises a set of auxiliary control flaps, or means, 12,1211, 2], 2la, 30 and"30'a, placed'flush in recesses or indentaone of thestabilizers.

tions l3, in the tail assembly I4 of an aircraft. H: are the usual elevator means in the stabilizers l6. I1 is the usual rudder means in the dorsal fin [8 of a plane. I also provide a similar structure in the front wings, in the form of auxiliary control flaps or means II, II a and 10 and 10a, as will be later explained. Each set of flaps I2, I20, 2|, 2la, 30,30a,1l,1|a, l0, and 100, are of the same design, operationvand construction, each being hinged on, a fixedpiivot at the forward arm portion 3| of the flap, for pivotal movement .-.away from the surface in which recessed at I3,

as indicated by the dotted arrows of Figure 4.

Looking forwardly from the rear of the plane,

flap-or auxiliary control means I2 is pivotally mounted at 20, flush in recess IS, on the left side of-the-"dorsalfin-58; spaced forwardly of th rudderiljls. Similarly, on the right side of that dorsal fin I so construct andi mount another identical such auxiliary control rudder flap or means l2a, eachmounted'for separate movement on opposite sides, of said fin, as illustrated; that is, flap I2 'is designed for operation on its forward. pivot 20 outwardly from and on the left side offi'n l'8, whereas flap 12a is designedif'or such operation on its forward pivot 20' outwardly from but on.the rightsideofsaid fin, l 8; Figure 4 illustrates-such identical construction with relation, however, to Since the structure of the fin. ifiiwithrelation to. my fiapsl2 and 12a, is the same, as stabilizer 6,,,and' fiaps 2 I and and Ma and .fifla, Ihave not felt it necessary, toduplicat'e ,theillustration. My. flaps2gl, Zia and 3,0 and3lla comprise my, auxiliary controlelevator means.

Similar, in-,construction, ,and, manner, of, operationofflaps, anemy pairs of auxilary aileron control..flaps,,1fl',,1llja. and H and 11a, in, the. front wings,..illustr.ated, in Figures 5.. and 6. It would be needlessduplication to illustrate or explain them in detail, as they, are the same. as flap- 20 of Figure 3.,- being designed, pivoted, placed. and

operated with relation to each, other and the usual aileroncontrol, 5] and 51a, just as, 20, 7211a and 311,. and .Bflaare; with relation to elevators l5.

, .Usualaileronsfill ,andtld are fixedly operablein opposition, to.eachothen-thatlis one up. and the other. down, .on1y-whereas, my. auxiliary. ailerons are notsolimited. H. canbeoperated to go up only. when 10a,.g0es=down, and .10 up only. when H argues .down, when desired, .butthey, can also be operated in any, other manner; for instance, to assist the elevators, for .eXamplein heavily loaded planes, 1 la..and,]fla, can each beelowered a suflicient amount to cooperate with-the-elevators-in raising the 'craft, by acting. as, skids for. raising whenloweredto the rightangle; and similarly for airebrakmg .andbringing a-or-aftout of a dive 11a angina, can .bedowered; also, if desired, toiairbrake the speedof a .craft'll and 'Hacanbe operated .inlopposition-toeach other, together. with, 1.0 andJDa also being operated inoppositionto each other, thereby creating air resistancebrakeage means whensaidauxiliary aileron control means are so used,

Auxiliary control elevator flaps 3.8, and 3911 are constructed and operated the same as the ones in correspondingposition on, the other side of the rudder, 2'! and Zia illustrated in Figure l, 2i and, 31! being onthe top side of theelevator andlzia andBil'a being on the bottom side thereof, looking, forwardly from, the tail, each in recesses I3 flush with the adjacentsurface and. each pivotally mountedat the forward portion or armstliereof 2ft, for pivotalmovement away from its respective surface.

Each of my auxiliary control flaps i2, l2a, 2|, Ma, 30, 30a, H, Ma, 15 and a. have a forward portion, 32 thereof, Figure 4, adjacent the hinge 20 cut-away to provide space so that upon the flap being pivoted upon its axis 29, away from its corresponding surface 34, as in Figure 3, there is then a space 32,'forward thereof, between the blade portion 33 of the flap and the corresponding surface 34. This structure in my aircraft flap or control or guiding means, is of utmost importance, as it permits an air pressure, or blast of air, to pass through that space 32, upon operation of my flap upon its pivot'20, adjacent and along the corresponding surface 34, without deflecting all the air away from that surface 34, as in Figure 3, thereby permitting usual normal operation of the following control surface placed behind it, such as the usual elevator l5v of Figure 3. This is true of each of my auxiliary control flaps or guiding means, so as to permit, rather than hinder, normal operation of usual rudder l1 and ailerons 51 and 51a. This cut-away portion or space 32 is the thing which permits placing one control means ahead of another, such as 2| ahead of IS, without sacrificing the operating efficiency of the following one. Taking the auxiliary means 2| as example, the space 32 of 2| permits air pressure or a blast of wind to pass through there, upon pivotal operation of 2!, adjacent the surface 34, to strikeelevator I5, and as a result the operation of 2| will not prevent or hinder the operation of IS in any way. This placing, of my auxiliary control means on the same surface and ahead of the usual control means, is made possible by my said construction of my auxiliary control means, whereby my auxiliary control means can be brought into use at will to assist or take the place of the usual control means by utilizing the same air pressure or blast of air along that same surface, as a result of space 32.

Referring now to Figures 3 and'4, for the balance of a sample construction of my auxiliary control means or fiap, my auxiliary controls are pivotally mountedat Zll and seated in a recess l3 flush with the adjacent surface 34. The inside of the recessed portion l3 of the stabilizer is closed except for slots 54 through which the flap is connected to a source of power. When power to pivot away from its seat or surface is not applied, the flap is normally held in its recess by means of spring 38, as shown with relation to flap Zia of Figure 4. Spring 38 connects the flap 2 la. to the source of power through arm 36, pivotally mounted in a roller 3! held in a U-shaped stationary uide rail 35 mounted between support beams 39 of the stabilizer structure. The other end of arm 35 is pivotally mounted at 51. Wire 5| connects the source of power to the flaps by passing over rollers 52 and 53 and being connected with the inward edges of arms 36 adjacent the axes of the rollers 31, whereby the flaps can be operated separately or in unison, as desired. Each conduction of power from the source is separate from the other, so that either or both of the corresponding member comprising the pair of auxiliary flaps, 2| or 2|a, can be operated when desired; and this is true with relation of each pair of my other auxiliary control flaps, 30, 30a, 12, I211, 10, 10a, 'H and Ha, with relation to each member thereof comprising the pair. When the power is applied through the cable 5|, in the directions indicated by the small arrows adjacent the springs of Figure 4, to operate the flap 2|, for instance, the arm 35 is pulled towards the stop 55 against the spring 38 attached to the roller 3'. in track 35, and as a result the arm 36 pivotally mounted at both of its extremities pushes the flap 2| portion 33 thereof, on its axis 23, away fromits corresponding surface 34, whereby the portion 33 is the desired space away from its adjacent surface 34 to provide the proper air pressure stress against that surface 34 for the desired auxiliary or only control means action at that place. The amount of power or pressure exerted through cable 5| controls how much space the portion 33 0f the flap is operated away from its adjacent surface 34. Upon release of the pressure, through cable 5!, the spring 33 quickly brings the flap back to inoperative position flush with its adjacent surface 34, in recess l3, and holds it there assisted by the air pres sure in flight. Recess i3 is completely closed from the outside, but for the slot 54 in which the arm 36 operates. 55 is a fixed maximum operable stop for the arm 36. 56 is a fixed stop for the flap 2| to rest against, being held there when not in use by the spring pressure and the pressure of the air in flight. Front edge of the portion 33 is at an angle to arm 3! as illustrated to prevent wind resistance building up against it upon use of the flap, and similarly with the trailing edge 57.

It is to be noted, in the embodiment of my invention illustrated, that my invention comprises a new kind of aircraft control flap or guiding means. I mount 5 pairs, or 10 of them, at five different places in the craft, for 10 independent controls or guiding means, if desired, each ahead of the usual rudder, elevator, and aileron control means; the elevators being one on each side of the rudder, and each pair comprising one on the upper surface and one on the lower surface. New uses and combinations of uses result from each of my said auxiliary, or main, control flaps or means being capable of operation independent ly of each other and of the usual controls of craft as heretofore known; preferably, constructing my controls each with a cut-away portion to permit wind blast to pass therethrough, in operation, for use of the usual controls following, but I do not mean to limit my invention to such structure, as that is but one embodiment thereof, illustrated.

Onemethod of operational connections for my control flaps or means is to so connect the cables 5|, being the same construction as in Figure 4, to the sources of power, whereby my rudder lZa will operate on its pivot when and as rudder I1 is moved to the right, proportionately thereto, and so that my rudder l2 will operate proportionately on its pivot when and as rudder I! is moved to the left; and so that my elevator 2| will operate proportionately on its pivot upwardly when and as elevator I5 is moved upwardly, and so that my elevator 2|a is moved proportionately downwardly when and as elevator 5 is moved downwardly; and whereby my elevator 30 moves upwardly proportionately on its pivot when elevator |5 moves upwardly, and so that my elevator 30a moves downwardly on its pivot proportionately when and as elevator I5 is moved downwardly; at the same time in the alternative, at the will of the pilot, another method of operational connection of my controls is to have them connected for individual or any desired combination of movement. My flaps 10, 10a, H and Ha, are to be similarly connected, with relation to the usual ailerons 51 and 51a, as will be more fully explained. It will readily be seen that my auxiliary controls will assist the usual controls in guiding the aircraft, .or in. event of inoperativeness of any one of the usual controls my corresponding auxiliary ones will take the place thereof in an emergency.

Various means may be utilized for operating my 10 auxiliary control surfaces, ll-10a, 10-! la, 12-42% 2l3il, and Zia-36a, independently, simultaneously with others, or in any other combinations, as well as a unit independently of the trailing edge controls, as will be explained, within theteaching of this invention. In Figures 8 and 9 of the drawings I illustrate one way of operating one set or type of my auxiliary controls, such as auxiliary ailerons 'lllila, and Iii-l Ia. Similar sets of circuits and switches as therein shown are provided for each of my other types of controls, the basis of each being as illustrated, I will now explain the one illustrated in detail. It is to be understood, with relation to this illustration, designed to operate all four ailerons 'H- illa and ML-Ila, that, for purpose of this illustration, a pair of ailerons, such as IL-lilo, are connected by any conventional system of cable and lever arrangement to one'cable 5!, of Figure 4, and the other pair of ailerons lib-Ha are so connected with another cable 5!, whereby actuation of one of said cables 5| will operate a pair of those ailerons, as will be understood in the art with relation to heretofore conventional trailing edge ailerons being operable in opposing directions as a unit. Said power cables 5| and 5|, one of which is so connection with one of said pair of my auxiliary ailerons, I l-Jfla, for actuating same as a unit in unison, and the other of which cables 51' is so connected with the other of said pair of auxiliary ailerons, IO- Ia, for actuating them asa unit in unison, my power means and circuits, are reactive to solenoids '15, as illustrated in Figure 8, with each cable 5| being connected to an armature 16 of a solenoid '55. The circuits of those solenoids are connected to several switches, there being several circuits in parallel to operate independently. One pair of circuits contains switches 11 and 'Il'a to alternately react,.with and in the same direction of operation of trailing edge ailerons 51 and 51a, the switches l1 and Ho being arranged on the conventional steering mechanism 18 to react alternatively as the pilot leans the stick sidewise to operate the conventional trail.- ing edge ailerons 51a and 51. It will be seen therefrom that as the pilot leans the stick to the left, and in so doing raises the trailing edge aileron 51a and lowers trailing edge aileron '51, that my auxiliary ailerons H and His, will be pivotally operated in unison in coaction with the movement of 51a and 51, by H being also raised and 10 also lowered; and as the stick is leaned sidewise to the right for actuatinga raising of trailing edge aileron '51 and a lowering of trailing edge aileron 51a, that other of my auxiliary ailerons, l0 and Ha, will be in unison in coaction with that movement of 51 and 51a. by 10 being also raised and Ha being also lowered. A throwout switch 13, located on the steering handle mechanism, disconnects the circuits containing the switches 11 and Na, for making the type of reaction just described inactive, as will be understood. Another pair of circuits contain the switches 80 and 8|, adapted foraselective operation of either pair of ailerons, Hand 10a, or Ho and 10, independently of the for example in describing pivotally operated i trailing ed e ailerons. .5 1 .5la, with the said switches, .80 andSl, being conveniently associt ith the steering mechanism 18. Double switch 82 operates .bothsolenoids 15, adapted for causing ,operationof both. of my pairs of auxiliary aileron control surfaces, He-1,00,, and Haill, simultaneouslyand independently of the trailing edge ailerons ELF-5.1a, as ior. air-braking reasons, which will be more fully explained. Since my invention also provides for selective use or op.- erationof oneor more-of .my said four auxiliary aileron flaps, 'H-JI WP'IM, for aileron. use or; other use reasons, as will be explained, therefore, obviously, in order to be able to so selectively operateany oneof said four auxiliary con trol surfaces, ll, Ha, 10 or 10a, independently of allother controlsurfaces, other circuits are pro.- vided for each of. my novel sets or types of. con.- trol surfaces, wherein there are four such .surfaces in number, as in the ,case of. the auxiliary ailerons, just described, and likewise in thecase of my four elevators, 2 lm2la,-=-3fl 3na, as will be understood, by providingtwo more solenoids and two more-selective switches and circuits in parallel, for thereby operating any one of such sets of four independently.

From the foregoing explanation of the power means and circuits used for operation of my auxiliaryailerons, it .willbe apparent that similar circuits and switches are provided for pivotal raising operation-of .myauxiliaryelevators 2 Land 3!) as a pair in coaction with and upon operation of trailing edgeelevators 15, as said elevattor-s H: are elevated, and for pivotal lowering operation of my auxiliary elevators Zlaand 39a as a pair in coaction with and upon lowering operation of trailing edge elevator l5; and with the provisionof four circuits, solenoids and sets of selective switches, adapted for selective independent operaticnof any one-of my four auxiliary elevators 2|, 21a, 30-or 3.0a, .or any combination of those four, for reasons to be explained; itbeing understood, in connection therewith, that the switches 11c and 11 thereof, instead of being positioned. sidewise of the stick, are, though not illustrated, obviously, positioned fore and aft of the stick, forthose circuits simultaneously operating either an upper pair of my auxiliary controlsas the trailing edge control is raised, or-forsimultaneously operating mylower pair of said controls as the trailing edge control is lowered, upon amovement of the stick aft or fore, respectively, whenthe simultaneously operable circuit isin :use; without necessitating further illustration and description,

Further, fromthe foregoing detailed description, relative to the,circuits andoperation of my ailerons, 1|--llap.-10-10a, it will be apparent thatthe circuitsshowninFigure 8 are also used for operatingmy auxiliary rudders l2 and i211, except that -I- provideatwo position, right and left contact, rotary. switch, associated with the steering mechanism, instead of the switches 11 and 11a, whereby,,when the wheel is turned to the left my auxiliary rudder I2 is pivoted from its surface'in coaction with and upon the main trailingedge, rudder ll being turnedto the left, as illustrated in, Figures 6 and .7, and when the wheel is turned to the right my auxiliary rudder I20, is pivoted from. its surface in coaction with and upontrailing'edgerudder ll being turned to the right. Selective and independent operation of my auxiliary-rudders, I 2 and He, is also-prov1ded 1n, these circuits, as previously explained with relati on to the circuitsfor my ailerons, two

AQQM circuits, solenoids and selective switches, as illustrated in FigureB, being sufiicient in this instance with relation to my auxiliary rudders.

7 By providing master switchto energize all solenoids of all three sets of circuits, just explained, obviously, and as will be understood, all ten of my auxiliary control surfaces, II, He, l 10a, 2|, 2m, 30, 36a, I2 and i211, may be operated as a, unit, for air-braking means; as will be explained. Other circuits than those explained may, obviously, be provided for the operation of my ten auxiliary controls, in various methods and combinations, within the spirit and teaching of this invention. A battery, or other source of power, 83 furnishes power for the circuits. Instead of mounting the switches, as illustrated, they may be mounted on a panel on a side of the steering column. It is to be understood, as within the teaching of this invention, that instead of solenoids for actuating the cables 5|, other suitable power means may be provided, such as electric motors, with reduction gears, circuits and switches, and that, suitable cut-oil switch means may be provided therewith .for controlling the amount of operation of each control surface, once started, in accordance with a selective determination therefor.

I will now explain some of the various new operational results or new uses from my said structural novelty and combinations.

The landing flaps of the average small airplane are suflicient to slow the speed of the plane for a safe landing. With larger, heavier and faster aircraft, however, it has been found that the matter of slowing the craft sufiiciently for a safe landing needs improvement over the heretofore conventional means used to accomplish that, if it is not one of the most serious problems of aviation. In aircraft having my auxiliary flaps that problem is not present. Reference is made to my Figures 5 and 6. Preparatory to landing, one or more of my flaps is pivotally raised away from its corresponding surface, sufficiently to form air pressure resistance thereagainst, in cooperation with the usual elevator means so as to keep the craft on the desired degree of descent; as illustrated in Figure 5; wherein my auxiliary ailerons a and Ha, auxiliary rudders l2 and [2a and the upper auxiliary elevators 2| and are pivotally extended, as illustrated, to assist the landingflaps 58 in air-brakingthe craft preparatory to landing, when also using the usual elevator in a downwardly position, illustrated in Figure 5. In such a combination just mentioned, it steadies the angle of descent by holding the tail upwardly against the downwardly thrust caused from the air friction against the flaps l2, 12a, 2| and 30 being extended, indicated by the dotted arrows of Figure 5; and in such a combinationthe said usual elevator means l5 has a. new use, namely, that of braking or landing flap means. Pressure against my extended flaps l2, [2a, and 2| and 30 cause the plane to lower its tail; and pressure against the lowered usual elevators I5 cause the tail to be raised sufficiently to counteract the downward thrust just mentioned; thereby creating a new and effective air-braking means to assist the usual landing flaps, 58. The proportion of said extension of my new flaps and of the elevators, just mentioned, with relation to each other, can easily be determined in advance with relation to the individual plane, so as to. have a normal'level, yet downward, glide for landingwhen desired. extremely heavy planes this ,will be .iound. to

be sufiicient air-braking means, in cooperation with the usual landing flap braking means, that thecraft will not have to circle the field several times to lose speedbefore landing, but will be 5 able to come in from a high altitude for a straight descent when desired. Advantages of this structure foruse in bomber o-r pursuit ship will be obvious My invention results, fromthe use just described,fi n the entire tai1 assembly of a craft becoming, in effect, braking means for the craft when desired in the air, as well as after the plane has landed, as illustrated further in Figure 6; which shows a plane having just landed wherein tail braking means just mentioned comprise my auxiliary rudders l2 and l2a, being extended, my auxiliary elevators 2! and 30, being pivotally extended u pwardly from the stabilizer, in conjunction ,with the lowered usual elevators l5 and the lowered landing flaps 58, all creating air-bralreage and thus assisting the wheel brakes in stopping the plane upon the landing run stop before it reaches the end of the runway. Of course, in extreme cases or with extra heavy or fast craft, more air-braking could also be had by also extending my upper and lower pairs of auxiliary aileroniiaps, ii and ill, and Na and ma; either alone or in combination with the other braking means mentioned. It is also obvious from my disclosures thus far, that my lower auxiliary elevator flaps. Zia and 30a can also be brought into play for air-braking means in cooperation with the air-braking means, 2| and 35, i2 and IZa, and elevators l5, illustrated and just explained, truly making the tail assembly a braking means when so used. Pursuit ships and dive bombers necessarily have to dive under power and attain terrific speeds, with the result that difficulty in raising the usual elevators l5, for pulling the craft out of 1:.- the dive or fall, is experienced. Under such circumstances, the use of my auxiliary control flaps, or elevator means 2| and 30 being pivoted or spaced away from their corresponding surface, will greatly help the usual elevators l5 pull the plane out of the dive and level it at the desired degree. As previously mentioned, my auxiliary rudders l2 and I 2a, when opposingly to each other extended in flight tend and do force the tail downwardly; so in the situation just mentioned of bringing a plane out of a dive, they also could be so used as speed braking and tail lowering means for leveling the craft if necessary, in cooperation with the usual elevators and my new auxiliary elevators.

It will'be obvious, that one of the functions or new uses of my auxiliary elevators or means for raising thecrait, is to raise the upper elevators 2| and 39 to assist the usual elevators l5, upon a take oil, in the event of a heavy craft or load, to prevent the plane overrunning the runway. Such a use will also be of value to the pursuit ship, for a quick climb preparatory to a backward up-side-down reversal to get behind an adversary before he realizes it. Speed is essential; so also is maneuverability; and my auxiliary control flaps or means provide safety and utmost maneuverability.

In the prior art, ailerons are fixed for operation, with relation to each other, so that when the one goes down the other goes up. As previously explained, my auxiliary ailerons Ill, Illa and 7|, I la are not so limited, but can have independent movement. vIt is also to be noted that my auxiliary control elevators 2| and 21a, and 30 and snag amiable or movement also iniiepei fleiitiy or one anetiien coulu as-a result, iriieedeuasast the usuaiailerons, by pressure exerted tlirooeh the tall structure, as diagrammatically illustrateiisoiid' iirieoe'sition my-auxiliary elewaters 2! andeflmof my Figure-"'7. I

Should the rudder ll be insufiicient to "left t'i'iin'tlieairplane-aroma craft; my aufiiiary rutfiier f2 can then be brought into ooeratiom by being p'ivo'ted outwardly from its corresponding surface-enough to'c'aus'e the desiredqeft and similarly, should the iiilider "ll -fail 'ori- 'a figfit turn, the auxiliary rudder *1 22 can then be tiyoted outwardly enough to cause the ii'esired rihttum. As' mentioned, the auxiliary e eva tr sil an 38 can be used to" assist the usuarela vators lain take-offer asent. Likewise; au iriii-ary lower elevators ea'n'be brought into use to assist the elevators l5, if necessary, control the degree or speed or descent cie's'ire'rl.

M auxiliary controls i1, 12 d, 2 I 2 1,-30 30a, Ill, 1%; ii and 1ia-,-are-net required tobamoved iiiieairs-, or-in unison; orinany 'p rtiemars'et oi oeinieinations or relationship, but -a're" mounted for" movement of any one or moreihde'penlient'ly ef the remainder. For instance, to bank'and turn theplane to tli'e'le'ft by mea'ns or" auxiliary fi'ehtiols', witliout i'i'S'iYlg' the usual on'ti'oi's; my i 2, 1ea-,- 3na, 2 i and T I eo'ulcl be ivoted away from the e spending surfa'c'e-"oi'ealilsee figure '1) and alien reverse-movement come he usel' by using 120516; ill), 2i and H by pivoting each-*away from its corresponding surface, to reverse the action; or suehe'fitire oomleihation need ntitb used if not necessary, such as the same result-in less'deg 'ree o'ou-l-d be aoeompl ished byusingeither i2 and :21 or l2cl and 38, respectively. ItW'iil 'tlilisbe elearlyseen that my aiiiilifi? coat'reis are riot-13211 3 auxiliary control-'5 E for steering -01 guiding -the iaft,-but also for-braking, assisting and supplementing any one or mora e e'i'iere tofo're known-means for contrellifi'g orfiiii'ing', an'cl 'a'ls'o brakin'g, respectively. Other numerous-benefits 'amdilse's frbiY-r'ii'iy constructicm will be at oneapparent= P culai'ly,- greater maneuverability or military e aft and greater safety of civilian transports o'f marrow will result. The ifutu-re -is e'xpeete' 430 have tailess planes, in the way --we:have us'ed them in the past that is, aircraft only one large wing, with control means inoonnection therewitli instead of the conventional-plane of today, and it appears that the motors will be placed in the rear. Such futureconstruction will make edge-flaps, ailerons, rudders and 'ele-f yator's'" 'difi'ioult of construqtionamt-operation I as not Wish to be confined in r-ny-inventiento t'otlayscofiiiefitidfial craft. of myauxillary eo'ritro'ls 'se't form, illustrated aria explainemeari just as Well he laeeci'iii'the surf't'Cie's'fif "a Ofi-WifiQ'iiilEl'i'', 'Iierix'iitt ifig' motors "to be placeni'att he edges thereof, and present "usual "edge"c'ohtrol mane-animated.

While I have thus "disclosed and described several referred embodiments of my iiiveritiofi, it is-apparent that many variations" and "changes may be made therein without varying froiii'or distinguishing over the spirit arrwseope army invention;

-Moreover, all of the features of-iny invention eeeu notbe usd= con-jointly, as the same mayiaf -usetl -to advantage in variously {iifierer'it' itb nations anti sub ciil'fibifiatifiiis -I fihe'if-di wlsh iii flaring thus inscribed-my invention, what claim as new and desire to tzove'r by" Letters Patent 1. Iri-ari aircraft, in combination, an airfoil having aobntr'l element pivoted'thereto at its trailing edge-arm swifiga ble in o'fapositefiiree'' tion's, a pair of like auxiliary control elements aaapteti ffbr the same type of r'zontzol as the trailing ed'e Control and being eaoh piv= cited-"wean airfoil andone on each sidetheie or armrest of saw first control element and with a: cut-away portion adj aceiit its Y pivot, 'e'ach' auxiliary control element being pivoted: at its rowel-(ledge, one of said auxiliary ontibl eieinentsbeingoperably swim-gable o'n'e 'dire tioii away from said airfoil and the other Mil i-'- i liary element being o'peratly swingabie i'ntfi other "direction ti'ierefroiii, and means for imie= bend'elitly' operating saiu auxiliary 'c'o'ntrol's whereio'yiri the' fliht ofthe air'c'araft's'o whmaii auxiliary control element is swing ably operated awayimm ne-adjacent airfoil surface a partof the'airstream passes through said cut-away'oor tion and between the auXi1iary'con'tr'01 element and'it'saadjacent airfoil surface to said'first oem trial element.

2. In an aircraft having-'air brakea'g'e means, in 'combina'tionyan airfoil having a control elesilentxplvoteii thereto at its :tr'ailingedg'e and swingable in oppos'ite' directions from a centrally substantially streamlined position, a pair oi' like auxiliary control elements arllaptezi' for the same type of'eontrol'asthe trailing edge control am] being eaohlpivote'dto said airfoil and-one :on each 1 sidethereiif in front o f said trailing edge eontrol element'anrl each having a out=away portion-adjacent -its pivot, ea'cii auxiliary control elemenbbeirigz piyoted at its forward eagegon'e of --.-sa-idauxiliary .eentrcii element's loeingswing :a'ble 'awa-y 'irom'zsaid airfoil in one direction and the-other beir'ig swing able' iiilthe' other dire= 'tion, -and mean's for simultaneously operating said auxiliary'eohtrol eeiements, wherebyiniifiiht of the airoraft'when said auxiliary control ele ments ar'e' so simultaneously voperated- 'a part or the airstreamipasses' througheachco'ut a'Wa-yoerti'on -andfibetweh its respective auxiliary element 'and a d jacent airfoil surface-to said first central element Y -3 .11; a n xairbi'aft i n eomliii aiaon an ai'zlil having: a control" elementpivoted. at the traiime edge of' the a'iifioil andst agable in opposite th reetionsyamair 16f like auxrliary aootrole'lemei its adaqatedl ior tiie same tyi e' ef control as the trail ingaeuge 'oohtrol' ai'qd being each pivoted atits iorwardwed eito saiuairioii from of said-tr i"- ing ed'ge feontrol element, each auxiliary centre! element'ihavinig a dot-away portion adjacent its pivotponeonsaiu aaizilif y-eor'itrol elements being operablq'ri swinable in on ec'ti'on away'fro'rii Saili airfo'il aflfl the" other am lia'ry element teiiig operably'swingablein tneother (i'i1i3CfiiO1'i"thE1= from, and means ior simultaneously operating on f-s' iiiiiliar co'rltroi eienientsar'idsaitl tra fig elg'fbehtrbleienielit, whereby in flight bf tlieairbfiaft when ar auxiliary control element aria th'fir'tfill'n' ede control element are so simultaneouslyosrateu-apart of the airstre'ani passes tfiio'llg-fi'fsaifiut away portion of said aaxiiia eoiitrol 'elemerlt and between said anisiiiai'y eontrol-fiement a "as aiijaceiitairioil surmis :tesaiatraiiir eee Control element; 4;an aireraxt;tl e coriibii iatioii-=with=air-ah l'o'il IiQJViIiQ' llDpF EtiiG lowersurfaees, aladitlg means associated therewith adapted for operation in the air-stream, of aircraft guide control means comprising a pair of guide control elements, each guide control element being pivotally mounted at its forward edge to said airfoil, one of said guide control elements being positioned on each side of the airfoil in front of said trailing edge means, and each guide control element having a cutaway portion adjacent its pivot, one of said guide control elements being swingably operable away from said airfoil in one direction and the other of said guide control elements being swingably operable away from said airfoil in the other direction, means for swingably operating each guide control element on its pivot independently of the other guide control element, and alternative means for swingably operating both of said guide control elements simultaneously in unison on their pivots, whereby in flight of the aircraft when a guide control element is pivotally operated a part of the airstream passes through said cut-away portion and between said guide control element and its adjacent airfoil surface to said trailing edge operative means.

WILBUR A. E. MITCHELL.

14 REFERENCES CITED The following references are of record in the file of this patent:

Number Name Date 1,056,844 Simpson Mar. 25, 1913 1,153,612 Erie Sept. 14, 1915 1,707,690 Sperry Apr. 2, 1929 1,841,804 Hall Jan. 19, 1932 2,043,275 Weick June 9, 1936 2,045,638 Dormoy June 30, 1936 2,064,970 Dornier Dec. 22, 1936 2,115,225 Zaparka Apr. 26, 1938 2,158,686 Barnhart May 16, 1939 2,170,787 Rose Aug. 22, 1939 2,194,796 Joyce Mar. 26, 1940 2,207,951 Stone July 16, 1940 2,322,745 Rogallo June 29, 1943 2,329,177 Baker Sept. 14, 1943 2,381,957 Ibarra Aug. 14, 1945 2,395,809 Goddard Mar. 5, 1946 FOREIGN PATENTS Number Country Date 167,260 Great Britain Aug. 3, 1921 365,537 Great Britain Jan. 18, 1932 448,827 Great Britain June 16, 1936 785,934 France May 27, 1935 Certificate of Correction Patent N 0. 2,480,040 August 23, 1949 WILBUR A. E. MITCHELL It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 61, for the Word rearwardly read forwardly; column 7, line 35, for connection read connected; column 9, line 7, after 70 insert a comma; line 10, after circuits insert a comma; column 12, line 19, before operating insert so; line 20, after aircraft strike out so and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 20th day of December, A. D. 1949.

THOMAS F. MURPHY,

'Assistant O'ommz'ssioner of Patents. 

